Twenty years ago yesterday, Dr. James Hansen gave a landmark testimony to US Congress in which he told senators that global warming was real, it was happening, and humanity was to blame.

Yesterday, he appeared before Congress, where he told most of official Washington we are now at the point of a “planetary emergency”.

For the low-down of yesterday’s speech, and links to the best media coverage, check out Alex Witze’s post over on The Great Beyond.

Olive Heffernan